We model fluorescence images of single molecules in spherical dielectric microcavities. Molecules are treated as time-harmonic dipoles. Images are integrated over emission frequencies. Because of the strong refractive properties of the enclosing sphere, the fluorescence image depends on the refractive index of the sphere and the position, orientation, and emission frequency of the molecule. When the dipole's emission is at the frequency of a microsphere resonance, the brightest regions in the images appear to originate from outside the sphere for some dipole positions. This type of calculation should help in interpreting images of molecules in microspheres.